To surround a section of code with comment delimiters or to prefix
every line in the section with a comment marker; this prevents it from
being compiled or interpreted. Often done when the code is redundant or
obsolete, but is being left in the source to make the intent of the active
code clearer; also when the code in that section is broken and you want to
bypass it in order to debug some other part of the code. Compare
condition out, usually the preferred technique in
languages (such as C) that make it possible.